feat(metadata-generator): Filter according to specified black/white lists

[mbektchiev]

Each text file contains a list of patterns of the form moduleGlob:symbolGlob,
where ? and * special symbols treated as any symbol and zero or more symbols.

A symbol is whitelisted if it's module name and native name pair matches a
pattern in the whitelist, or if a whitelist file is not passed as an argument. All
symbols which are not whitelisted or match a pattern in the blacklist are
excluded from the global table of metadata symbols.

• Update metadata-generator submodule
• Add a blacklist.mdg file to TestRunner and symlink from the root (because
  SRCROOT of TestRunner points to the directory of the main CMakeLists.txt)
• Add a unit test which checks for the correct filtering of metadata according to
  the rules in blacklist.mdg
• Add test case with function returning a struct which is blacklisted
  If a struct's metadata is missing it's not possible to silently ignore it and
  perform the call, because we don't know its size and cannot reliably
  allocate the stack frame for the cif. That's why we'll abort the call and
  throw a JS exception
• Add test case with functions returning and taking as an argument
  objects from a blacklisted class. In this scenario the behavior is the
  same as with objects from private classes
• Use Objective-C exceptions to propagate errors when filtered
  metadata is used and handle them in JSC callbacks
• Update metadata generator to use native names in type encodings
  to allow correct discovery of interfaces and protocols when they
  have been filtered

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/ios-runtime/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
• Tests for the changes are included.

What is the current behavior?

Metadata is generated for all discovered supported native symbols

What is the new behavior?

Metadata can be filtered by specifying a whitelist and/or blacklist in
two files residing in $(SRCROOT) (blacklist.mdg and whitelist.mdg).
Each line should be of the form module-name-pattern[:symbol-name-pattern].

refs #1209