Clean up whitespace

Although the source code uses space characters for indenting, some lines
contain tab characters. Clean up these lines.
Add '.gitignore'
Mark 'install' target as phony target in Makefile
Add 'all' target to Makefile

Add an 'all' target to the Makefile and make it the default target as
is customary. It is useful for a clean rebuild:

    make clean all
Merge pull request #2 from jvirtanen/cleanups/whitespace

Clean up whitespace
Merge pull request #3 from jvirtanen/cleanups/gitignore

Add '.gitignore'
Merge pull request #4 from jvirtanen/features/make-all

Add 'all' target to Makefile