add docs for executeAndFetchLazy
clean up executeAndFetchLazy docs
changed 'latest version' to 1.3.0
moved 'Fetching data lazily' menu item, so it is placed directly below 'Fetching data'
changed download page to reflect move to central repository
added a new changelog page
updated link to change log from 'home' page
Merge pull request #48 from aaberg/gh-pages_1.3.0

add docs for executeAndFetchLazy
updated download page and changelog