Updated README.md text from 'Another samples' to 'Additional Samples'

Updated the text of line 13 in README.md from 'Another samples' to 'Additional samples' to improve clarity regarding the plurality of samples available in the repository.
added start and end callback for zoom
Add index to tooltip name format function
Make nameFormat arguments the same as valueFormat
Updated Readme for readability

Fixed some grammatical errors
Add ability to use data ids in label formatting on pie chart slices
fixed error caused by function in config.data_order
added test for function in config.data_order
Fix axis.y.min/max when smaller/bigger than targets' - #562
Set z-index for tooltip in css - #564
Modify step chart interpolation - #566
Merge pull request #568 from ateich/patch-1

Updated README.md text from 'Another samples' to 'Additional Samples'
Fix axis x clip with padding - #446
Fix padding when rotated
Merge branch 'master' of github.com:masayuki0812/c3
Fix conflict
Merge branch 'michalkop93-zoom'
Update sample for zoom callback
Fix onclick/onmouseover on bar chart as each - #390
Add dependencies to package.json