Install server certs to android platform, fix elements, prepare for ios certs.

- Implement optional regexp matching of source files, utilized when
  SourceFileName starts with a "^".
- Revised elements.json to use this for new Android and iOS
  .cer certificate entries, and also for already existing iOS splash
  screen entries.
- Eliminate separate FileName versus SourceFileName/TargetFileName. Keep
  only the latter, and use the SourceFileName for the target if no
  TargetFileName is specified.
Create harness for iOSaddCertificate action.

Functions implementing actions must be explicitly included in
targetActions variable to be used, to preclude (inadvertent or
deliberate) misuse.

This is ready for adding node-xcode code to incorporate the certs.
Gracefully skip platforms that aren't yet created.

Unfortunately, the after_prepare hook is being called after each
platform is added, rather than after all are added. We were emitting
warning-ish messages for each copy attempt to the missing platforms, now
we just emit one saying the platform is not yet present.

Eventually, we should also stop repeating customizations for platforms
that have already been done - will be sufficient to leave a file marker
in the platform dir to detect, since platforms are wiped on brand
changes.

Also, clarified the log messages.
Incorporate aluny's node-xcode facility, and start to use it.

It's not yet working, I'm hoping because I don't yet properly place the
cert files in the project hierarchy.
Get iOS cert placement working.

- Include copying of cert files in place and aluny node-xcode addResourceFile.
- Normalize action to include target location as well as source, in case
  some future action requires it
- Explicitly include source directory argument in doCopyIfPresent,
  rather than getting it as a global.
- Rectify paths in general.
When adding iOS certs, write the changed project.pbxfile.
Reload and parse the iOS project each time we're going to change it.
Merge pull request #595 from SpiderOak/place-certs

Place certs