Added few config options

- Added sufix and prefix for label
- Added opacity option for chart
- Added configuration to show or hide ticks and subticks
- Fixed issue when giving custom config with download option
Merge branch 'master' of github.com:Imaginea/uvCharts

Conflicts:
	src/gfx/graph.js
	src/util/config.js
Merge pull request #33 from priyankadudani/master

Added few config options