inhibit change hooks during (insert content)

`yas-expand-snippet' narrows to a 0 size region before doing (insert
content), this confuses cc-mode's before-change-functions that
invalidate some cached information. Binding `inhibit-modification-hooks'
to `t' prevents calling these functions.

Fixes #404.
add: test for issue #404
fix: don't use universal-argument-num-events
Revert "inhibit change hooks during (insert content)"

This reverts commit 90d4cae1b1bbfacc612e73444f1e5a723ae4036e.
wait till after content insertion to narrow

Fixes #404 without inhibiting change hooks.
Merge pull request #409 from npostavs/font-lock

Fix yas--font-lock-keywords
test middle-of-buffer snippet insertion
Merge pull request #412 from npostavs/less-narrow

Wait till after content insertion to narrow