code review changes round 1
Merge branch 'develop' of https://github.com/Sage-Bionetworks/SynapseWebClient into develop
and do not enable add page button if can't edit
add Wiki place token test
code review changes 2. clear references when attachment is deleted, and insert preview reference when attachment is clicked.  use foreach, and other cleanup
hide wiki command bar if wiki is not editable
Merge pull request #197 from jay-hodgson/develop

code review changes round 1