src/dfinstancelinux.cpp: checksum: readAll on Qt4

Less efficient, but QCryptographicHash doesn't support passing in
QIODevices on Qt4. Fixes #121.
Merge branch 'gitignore' into DF2014
Merge branch 'qt4hash' into DF2014
Merge branch 'share' into DF2014

Conflicts:
	.gitignore
Merge branch 'stderr' into DF2014
Merge branch 'travis' into DF2014
Merge branch 'warnings' into DF2014