Made requires work with browserify
Added stability on bad serial reads
Moved serialport to optionalDependencies and added handling code.
Fixed undefined error
more strict for jshint
Removed unnecessary line
Moved serialport from optionalDependencies until browserify is smarter. 

It uses it's parents node_modules. browserify doesnt seem to look there.
Revert "Removed unnecessary line"

This reverts commit 591f25c607eed6e55c282427b37b242a8511b2fc.
Merge branch 'pr/49'