Accept lower-case versions for SRC blocks, etc.

[AdamFrey]

Hi!

Newer versions of Org mode since this commit (https://code.orgmode.org/bzg/org-mode/commit/13424336a6f30c50952d291e7a82906c1210daf0?style=split) default to using lower-case versions of blocks BEGIN_SRC -> begin_src. Both versions are acceptable to Org, but this library only looks for uppercase versions.

I know @eigenhombre that you aren't really using this library anymore, so if you are interested, I'd be willing to take over some maintenance duties for this library, as I use it in my blog generation. I'd rather help this library along vs forking and putting another artifact name out there.

[eigenhombre]

Would happily take a PR for this issue @AdamFrey ...

[garlic0x1]

Would happily take a PR for this issue @AdamFrey ...

PR submitted

[eigenhombre]

Merged PR and added tests.

[eigenhombre]

This is on Clojars now as clj-org 0.0.3.