https://issues.adblockplus.org/ticket/1050

create shread project with shared files

Previously they were included into each project.

Some benefits from it:
- DRY, it's already used by AdblockPlus, AdblockplusEngine and by tests
- Less compilation time.
- Theoretically it can happen that in tests there are some defines which change
the code. Linking the same library we have the tested code.
- No repeating - less disorder.
- Also one have to be sure that it's compilable in all projects instead of in
only one.