Skeleton project data

Update gtest to 1.7

When giving a custom comparison in std::sort use < as operator (not <=).

geometry->geometrical_set, patch->geometry.

This fixes crashes in debug mode (especially in some tests) in which case the
runtime checks this rule and quits execution on violation.

Now all branches will be tested by Travis.

Require minimum gcc version to be 4.8.1.

This enables testing on developer repositories.

Also clarifies the debug message in ctor.

This removes ProjectData ctor;

Also clarify an error message and the TODO for meshes.

Also update gui for moved ProjectData.

This contains just ProjectData for now.

This breaks some code. See following commits for recovery.

Most of them are not needed anyway but GEOObjects.h.
ProjectData is needed in single place only.

Also remove superfluous and wrong comments.