Bug 1069017 - Add a flash.sh target ("shallow") to flash gecko and gaia.  r=mwu

This is useful when updating a tree to current source and reflashing.
It's useful to have a single target for two reasons:

 (1) it saves waiting for the device to reboot and typing another
     command.

 (2) there's code that runs at startup to reregister gaia apps when the
     gecko version or build id changes.  If you reflash gecko, reboot,
     and then flash gaia, this code doesn't get invoked correctly with
     the new gaia.  See
     https://hg.mozilla.org/mozilla-central/file/4f2cac8d72da/dom/apps/AppsUtils.jsm#l482
     and its callers.
Bug 1073515: report the complete symbol correctly. r=dhylands

To remove the source file path and source line components from the
breakpad resolved symbol, we used a simple string split operation
separated by whitespaces. This had a side effect when the symbol
itself contained white spaces.

We now preserve the source file and line number information, but we use
only the basename path for symbol location info.
Merge pull request #387 from dbaron/bug1069017-flash-target-gecko-and-gaia

Bug 1069017 - Add a flash.sh target to flash gecko and gaia.
Merge pull request #391 from walac/bugz/1073515

Bug 1073515: report the complete symbol correctly.