cider-jump-to: Always jump to absolute line number, refs #737

Fixes invalid line offsets, when the buffer was already visited and the current
line number position is > 1
Remove non-interactive use of goto-line, refs #737
Merge pull request #737 from juergenhoetzel/fix-cider-jump-to

cider-jump-to: Always jump to absolute line number
Use `cider-from-nrepl-filename-function` to translate nrepl filenames

Add a default implementation on cygwin systems utilizing "cygpath" to
translate native filenames to cygwin filenames.
Use `cider-to-nrepl-filename-function` to translate Emacs filenames

Add a default implementation on cygwin systems utilizing "cygpath" to
translate cygwin filenames to native filenames.
Remove redundant var: Refs #735
Add a changelog entry for Cygwin support. Refs #735