Follow up of #68

Try to be consistent across the different stylesheets and fix the CSS
for the rails theme.
Move version to separate file, remove require_relative from gemspec
Merge pull request #73 from krautcomputing/fix_gemspec

Move version to separate file, remove require_relative from gemspec
Push ./lib to $LOAD_PATH for require SDoc::VERSION
Merge pull request #70 from robin850/css-fix

Follow up of #68
Initialize SDoc namespace in main file
Merge pull request #74 from krautcomputing/fix_loading

Initialize SDoc namespace in main file
Don't accidentally commit rails, since I often use it for testing.
Relax JSON dependency to ~> 1.7, >= 1.7.7
Merge pull request #75 from strzibny/fix-json-dep

Relax JSON dependency to ~> 1.7, >= 1.7.7
bump version