Improve docs for (.) a bit

Preparing for possible rename to (<<) which actually looks like an
infix operator.
Add note about Debug.crash
Add note about --bundle-runtime flag
Fix comment for String.lines

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Merge pull request #685 from alexander-b/linescom

Fix comment for String.lines
Update to use new testfile location
Update IO submodule and use newly supported type aliases
Update test file for stricter import rules
Update Elm-Test submodule
Merge pull request #690 from maxsnew/test-fix

Testing Fixes for Canonicalize