Significant updates to download page. Better flow, both for noobs and pros, with  links to PGP and SHA1 resources.
Tweaked maven anything-url-search field. Removed dup "AND AND" bool modifier.
Source: {Maven|Sonatype} links to anything search, rather than dist search.
added html file extension for the release-notes
Added verify page for checksums and keys
Added information about semantic versioning.
Fix BasicTaskExecutionTest.testScheduledTaskExecutedAfterDelay

- Failed in buildhive with:
  (actualDelay=40) not greater than (delay=100 + earlyReturnGrace=25)
- Fix is to start stopwatch before calling submit.
  Also increase "maxOverhead" to avoid similar errors in the other
  direction.
Tweaks to versioning closing.
Merge pull request #698 from jdtoy/semversioning-master

Docs: info semantic versioning.
Improvements to Verification page.
Merge pull request #685 from grkvlt/download-page-simplification

Download page simplification
Merge pull request #699 from aledsage/fix/BasicTaskExecutionTest

Fix BasicTaskExecutionTest.testScheduledTaskExecutedAfterDelay