smarter reassignment of fragments on section changes. see #499
Merge pull request #508 from martypdx/shortcircuit-reassignFragment

Smarter reassignFragment on section changes
keypath resolution should be attempted AFTER upstream changes have been flushed, in order to sync downstream values between sibling components
Merge pull request #510 from RactiveJS/siblings

keypath resolution should be attempted AFTER upstream changes have been ...
remove unused variable who came along with copy paste
test and fix for #499 additional test case: Section with nested sections and inner context does splice()
Merge pull request #512 from martypdx/shortcircuit-reassignFragment

Test and fix for #499 additional test case: Section with nested sections...
resolve merge conflict