Allow methods terminated in '?' when searching specs

I have found a bug where `rspec--toggle-spec-and-target-find-method`
would not work if the `method` name ended with '?' as in ruby
predicates.

This commit address this issue by using the `regexp-quote` before
formatting the `target-regexp` used for finding the method/spec
definition in the target/spec file.
Allow methods terminated in '!' when searching specs
Remove unnecessary quoting of ? and ! in regexp
Merge pull request #98 from rranelli/master

Allow methods terminated in '?' when searching specs