Block binding: fix useless variable rename for some VAR scoped declarations

Closes #1323
Block Binding: hoist function declaration in block to beginning of block

Closes #1304
Block Binding: use orignal name where possible

Closes #1274
fix export default parsing
Enable block binding by default

Issue #1277
Fix repl after #1331 broke it.

Fixes #1351.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1353

Closes #1353, closes #1351.
Deps need only ModuleSymbol info

Part of a refactoring to use Compiler in Loader.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1349

Closes #1349.
Cleanup

Fixes comments in BlockBindingTransformer

Fixes FindUnusedImports (it broke due to compiler changes)

Remove unused imports
Manual update to verions 0.0.64 and ignore compat errors

TBR=@arv

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1357

Closes #1357.
0.0.65
fix export default class declaration
Fix repl options menu

Fixes #1334
Block binding: Handle nested scopes better

Issue #1358
0.0.66
Pass metadata to REPL onFailure.

Show transcoding if the error is an evaluation error.

Fixes #1373

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1375

Closes #1375, closes #1373.
Use Compiler API in Loader.

Now our command line always runs through our Compiler API.

Fixes #1324

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1355

Closes #1355, closes #1324.
overrides native Map if entries() is undefined

relates to #1301
Make sure native symbols work

Do not overwrite the native Symbol if present.

Instead of enforcing that our shim symbols are non enumerable we
now generate code to filter out symbols for for-in loops. This allows
us to remove $traceurRuntime.setProperty since it is now OK to use
the standard browser [[Set]].

For the class runtime we need to iterate over the symbols too.

Fixes #1330
Partial support for destructuring in block binding

This handles patterns in let and const declarations but not yet
in loop headers.

This also simplifies the generated code, in that it does not
hoist a variable declaration when it is not needed.

Issue #1276
Pass file name to traceurRequire to give better error messages.

Adds test for error and its content.
Fixes #1380 using the sugegstion of @spadgos

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/1383

Closes #1383, closes #1380.