Music support (#270) + update version to 4.2

* Add initial music decompilation support

A lot of work still needs to be done, and a big refactor. But you should
be able to extract music out of a vanilla rom with this.

* Fix error with filename processing in MusicModule

* Add `songs.yml` output

* Add support for in-engine songs in `songs.yml`

* I think it works

* Output instrument pack numbers as hex

* Tighten up some error messages

* Deal with phrase list jumps properly

* Bugfix

* Finalize music support, including in-engine songs

* JK it's not done. Add todo comment

* Add support for editing engine.bin

* Code cleanup to address pylint warnings

* Nvm. Change version name to beta

* Windows build fixes + fix gas station + debug messages

* Fix palette bug and bump version number

* Add Gas Station instrument pack fix

See comment in MusicModule for more info.

* Fix bug with splitting Gas Station Pt. 2

Turns out, hash() of a 32-bit int does not give the same result on different platforms (32 vs 64 bit). Use crc32() directly instead.

* Update CCScript version

* Update version string in preparation for release

* Update CCScript link to 1.500 instead of master

* Use new upgrade code with recursive structure

* Update release date

coilsnake/assets/ips/Earthbound/gas_station_pack_fix.yml

@@ -0,0 +1,4 @@
+Title: Fix pack variable initialization to allow for custom instrument packs on the Gas Station (Part 1) song
+Author: cooprocks123e
+Hidden: True
+Ranges: []

coilsnake/assets/modulelist.txt

@@ -1,5 +1,6 @@
 common.UsedRangeModule
 common.PatchModule
+eb.MusicModule
 eb.CharacterSubstitutionsModule
 eb.CccInterfaceModule
 eb.SkipNamingModule

coilsnake/model/common/blocks.py

@@ -16,6 +16,19 @@ def check_range_validity(range, size):
     elif (begin < 0) or (end >= size):
         raise OutOfBoundsError("Invalid range[(%#x,%#x)] provided" % (begin, end))
 
+def fix_slice(key, size):
+    if not (key.step == 1 or key.step is None):
+        raise InvalidArgumentError("Slice step must be 1 or None, but is {}".format(key.step))
+    start, stop = key.start, key.stop
+    def fix_single_index(x, default):
+        if x is None:
+            x = default
+        elif x < 0:
+            x += size
+        return x
+    start = fix_single_index(start, 0)
+    stop = fix_single_index(stop, size)
+    return slice(start, stop)
 
 class Block(object):
     def __init__(self, size=0):
@@ -105,6 +118,7 @@ def write_multi(self, key, item, size):
 
     def __getitem__(self, key):
         if isinstance(key, slice):
+            key = fix_slice(key, self.size)
             if key.start > key.stop:
                 raise InvalidArgumentError("Second argument of slice %s must be greater than the first" % key)
             elif (key.start < 0) or (key.stop - 1 >= self.size):
@@ -132,6 +146,7 @@ def __setitem__(self, key, item):
                 self.data[key] = item
         elif isinstance(key, slice) and \
                 (isinstance(item, list) or isinstance(item, array.array) or isinstance(item, Block)):
+            key = fix_slice(key, self.size)
             if key.start > key.stop:
                 raise InvalidArgumentError("Second argument of slice %s must be greater than  the first" % key)
             elif (key.start < 0) or (key.stop - 1 >= self.size):
@@ -164,9 +179,13 @@ def __eq__(self, other):
     def __ne__(self, other):
         return not (self == other)
 
-    def __hash__(self):
+    def crc32(self):
         return crc32(self.data)
 
+    # Don't rely on this having the same result on different machines!
+    # Use self.crc32() if you're comparing with a known CRC value.
+    def __hash__(self):
+        return self.crc32()
 
 class AllocatableBlock(Block):
     def reset(self, size=0):