Merge branch 'release/0.0.2' into develop
Added basic PVGroup syntax

Added PVGroupStarter
Added syntax checks for all cases (please check and verify it)
Refactor file structure

Separate header and implementation
Add PVEntity for defult return holder.
Implement basic group

Applied ```_PV``` prefix
Removed PVEntity
Fix spec.
Add more tests

Add merge logic.
Added "_" prefix to protocols
renamed all types; exposed context;
Merge branch 'develop' of github.com:DAlOG/Parus into develop
Moved VFL implementation to PVVFLImp
Update README.md

Added 2 basic examples, single constraint and VFL
Update README.md
Add more tests

Add unimplemented tests
Merge branch 'develop' into group-support

Conflicts:
	Parus.xcodeproj/project.pbxproj
Reorganize code

Add separated groups, add common header.
Add VFL and Single layout support

Add tests for group
Add building VFLs
Add building layout
Add tests and context merging

Add group context
Add context merging
Add default options value
Add some tests to VFL
Small pbx proj updates

Move common h file in up of groups
Fix warnings.

Remove redundant cast
set instancetype as return in init. For clarity
Merge pull request #25 from DAlOG/group-support

PVGroup support
Structure refactoring
Global header