Implemented 'safeasi' option

When using Automatic Semicolon Insertion there are
certain edge-cases that you need to keep in mind.
Namely new lines starting with either `(`, `[` or
`/` because those may mistakenly be interpreted as
continuations of the previous line.

If you enable the 'safeasi' option jshint will
watch out for all the potentially unsafe
edge-cases, so you don't have to.
Merged `safeasi` option into `asi`
Merge pull request #1428 from Wizek/2.x

Extended `asi` option to be safer