Update README.md
Update README.md
Update README.md
added ability to customise 'no data available' text and added an optional description
fix a couple of npe caused by user tapping on a chart which has no data
improved performance by increasing the index of for-loops properly
Merge pull request #31 from yocaba/master

improved performance by increasing the index of for-loops properly
Merge pull request #30 from emmaguy/fix_npe_no_data

Fixed NullPointerException when no data set.
Merge pull request #29 from emmaguy/customise_no_data_text

Added ability to customise 'no data available' text
Merged pull requests.
Added dialog for example that the feature drawing into the chart by gesture is currenlty not available.