lib/jsminify: Added uglify.split_lines call

UglifyJS `gen_code` does not call `split_lines` automatically.
The command-line tool calls it: https://github.com/mishoo/UglifyJS/blob/master/bin/uglifyjs#L316
lib/jsminify: Reordered uglify.split_lines call to avoid empty line after the preserved comments. Removed empty lines at the beginning.
Merge pull request #3 from sompylasar/patch-1

Limit the number of characters on a single line