add deb/rpm for 2.11.0-M5.
update the main download page to 2.10.3.
update the API Docs page for 2.10.3.
switch to shorter and cleaner URLs for API docs.

the /files/archive part of the URL is sort of an implementation
detail. This just replaces "/files/archive/api" with "/api".
Merge pull request #126 from gourlaysama/fix/releases

Fix update to 2.10.3 and add back deb/rpm for M5