truncate potentially long CompositeErrors

If you have a typo in a task on 100 engines, the local exception will be a bit ridiculous.

This defaults the truncation to 4 tracebacks (could be even fewer, or even one?),
and you can set the tb_limit attribute of CompositeError to adjust this.

Prompted by [this SO question](http://stackoverflow.com/questions/14635935/silence-or-condence-ipython-parallel-exceptions).
fix celltoolbar layout on FF
fix button css
remove one useless element
get monospace pager back
make baseProjectUrl a method in Menubar
add option in menubar to set baseproject url
make base project url a method on notebook list
change more baseurl
pass baseUrl as option
next release will be 1.0
catch AttributeError in cleanup_connection_files

can be triggered during garbage collection (os.remove is destroyed before the KM instance)
Revert "patch deletion in codemirror"

This reverts commit 331a5f7fe85a6e894c35b64cd7987ed53f59ea57.
monkey patch codemirror with new functionality

use marijnh recommended way:
https://github.com/marijnh/CodeMirror/pull/661
fix a few remaining KernelApp/IPKernelApp changes
update cm update instruction
skip remaining ipc test on Windows

ipc is not a valid transport on Windows.
Merge pull request #2905 from minrk/kernel_parent_config

fix a few remaining KernelApp/IPKernelApp changes
fix last remaining KernelApp reference
Merge pull request #2908 from minrk/onemoreip

fix last remaining KernelApp reference