Ignore more filesystem objects

Conflicts:
	.gitignore

[ci skip]
Disable notifications to soci-devel (temporarily)
Initial Travis CI build matrix for backends
Add extra blank line

Trigger build for github.com/mloskot/soci fork
Remove backend-specific commands from before_script.sh

Remove no-op scripts, allow non-existent before_script scripts.
Make no-op script step verbose
Use TRAVIS_BUILD_DIR to locate scripts
Use TRAVIS_BUILD_DIR to locate builddir
Correct script missing error
Format .sh scripts
Testing source location for CMake
Use TRAVIS_BUILD_DIR to locate sources for CMake
Correct build/source locations for CMake

Add -e to shebang.
Add CMake options for empty backend
Use TCI_ prefix for custom variables.
Still fixing source location
Delete unused script
Clean up source locations clash
Still testing source locations
Still testing source locations
Still testing source locations
Still testing source locations