Update for glfw-rs bugfix
auto merge of #750 : kmcallister/servo/glfw, r=metajack
Modify Readme for png module.
Merge pull request #754 from saneyuki/readme

Update Readme for png module.
auto merge of #726 : metajack/servo/dlist, r=jdm

r? @jdm
Handle flow trees with block children of inlines.
Handle splitting inlines with interior blocks correctly.