boot.js passes the absolute path to the loaded source

relative paths confuse node-inspector and possibly other tools
Reference source-map in the server-side code's source

It is not needed for mapped stack-traces but is necessary for node-inspector.
bump dev bundle; upgrade node
Merge branch 'dev-bundle-0.3.38' into devel
Use the filepath from builder in the sourceMappingURL ref
Prefer += operator for strings concatenation to String#concat
Resolve paths with path.resolve
For files with source maps, use absolute paths map the stack-trace. If no source
map found, don't bother.
Update the comment
Merge branch 'server-source-maps' into devel

Enables the support for source maps for the server-side code.
It is very useful when toolings like node-inspector or node-profiler are used.
Adds UI._parentData(n) method in template helpers.

This method returns the parent data context which surrounds the
helper call. This mirrors the effect of {{..}} in Spacebars. So
UI._parentData(2) is equivalent to {{../..}}.
Update History.md with 'UI._parentData(n)'.
Fix quotes in History.md
Upgrade Less from 1.6.1 to 1.7.1
Update history
Fix "Email already exists" error with MongoDB 2.6

Fixes #2238
after startup, Meteor.startup(c) should call c now

This was the client behavior and is now the server behavior as well.

Fixes #2239.