Added better UDP example usage

Added UDP single char echo example for the UDP class.
Added to TODO
Merge branch 'master' of https://github.com/spark/docs
Libraries section refactor
Small tweaks to libraries section
Merge pull request #157 from technobly/master

expand code kerning a bit, fix issue with button text wrapping
Further improving code kerning
Merge pull request #156 from blakejakopovic/patch-1

Added better UDP example usage
Tweaked the TODO
Merge branch 'master' of https://github.com/spark/docs
Add item to TODO
Added complementary API call example for Spark.publish()
Update firmware.md
Update firmware.md
Added {{assets}} tag for MKIT datasheets

None of the maker kit data sheets are loading, I believe because they're missing the {{assets}} tag in the directory reference.
Formatting - missing close code block mark
Merge pull request #161 from dataxpress/patch-1

Formatting - missing close code block mark
Updated Firmware.md

Removed unnecessary whitespace from TCP example
Merge pull request #162 from blakejakopovic/patch-2

Removed unnecessary whitespace from TCP example
for kenneth - added missing pinout for servo