Adds expm(A::Hermitian)

Uses eigenvalue decomposition to compute expm(A). This is a stable method for
Hermitian matrices and is about 2x as fast in my testing.
Make event loop use run_once/process_events
Add test for Hermitian expm.
testing for git transactions; caught some broken cases.
Fix #2644
fix a typo in stdlib doc
Merge pull request #2647 from KDr2/master

typo fix in doc
simple Rest iterator
Event loop work
Merge branch 'kf/reviewme'
fix undefined reference problem in flush_gc_msgs
call flush_gc_msgs less often
Adds tests of simple tridiagonal operations
Merge pull request #2656 from jiahao/symtridiag-tests

Adds tests of simple tridiagonal operations
Merge pull request #2631 from blakejohnson/hermitian-expm

Adds expm(A::Hermitian)
update keyword sorters to evaluate default expressions lazily, and
handle rest keywords
Merge branch 'master' of github.com:JuliaLang/julia into jb/kwargs