Feature Request: Per project language intelligence settings

[gknops]

Often when opening some project I just want to have syntax highlighting and folding support, without seeing a million issues flagged because the toolchain setup is missing includes etc.

Actually I'd prefer that to be the default.

[gknops]

Also: How can I get Icarus to pull in a default header file in an Objc-C project? I have many default imports in my GCC_PREFIX_HEADER.

[mdk]

Somewhat related: #21