add linker calling convention (:convention: before linker file name) for windows, use specified file name instead of /usr/bin/gcc for gcc calling convention on Unix

Improve handling of import code from library

See merge request !26

On Windows:
- Items starting with -l are ignored
- Everything else is treated as an ASCII library file

On other platforms:
- Items starting with -l are treated as shared libraries
- Items containing a dot are treated as normal files and linked
- Other items are ignored

This allows one to use for example:

	import code from library "mylib_library"
	import code from library "-lmylib"

(where Clean System Files\mylib_library refers to mylib.dll or so).
The first entry is used on Windows; the second on non-Windows.

On non-Windows systems, allow `import code from library "-l..."` to link shared libraries

See merge request !25

set return code to -1 when failing to compile a single module

See merge request !24

Use separate link options file for the bytecode linker to avoid long command lines

See merge request !23

Add descriptive error when the command line is too long (for large projects in...

See merge request !22

Add descriptive error when the command line is too long (for large projects in Clean installations far from the filesystem root)

Fixed accidental removal of setting project path in ps state

See merge request !21

Fixed return type in cpm project file for macos

See merge request !20

Cpm project templates

See merge request !19

Set ByteCode path in project files by default

See merge request !18

Add new settings to set command of cpm CLI

Closes #3

See merge request !17