Add command line option --module <module-name>.

  Allows scripts and modules to be compiled in any order.

Review URL: https://github.com/google/traceur-compiler/pull/1064

Closes #1064.
Only add System.get() evaluator for modules=register.

Fixes #1066

Review URL: https://github.com/google/traceur-compiler/pull/1067

Closes #1067, closes #1066.
Destructuring and cover grammar fixes

This changes the strategy from using a transformer to transform the
cover grammars into rewinding the scanner and reparsing using the
target grammar.

This also introduces a AssignmentElement which is used for the
elements of the assignment pattern (like BindingElement which is used
for binding patterns (and default parameters).

Fixes #183
Fixes #836
Fixes #838
Fixes #969
Fixes #1015
Typos

Left over fixes from 1f117083158f42ad3195af7e5399955a62101fa9
Polyfill Reflect.global

Review URL: https://github.com/google/traceur-compiler/pull/1070

Closes #1070.
Generate code that uses Reflect.global for global

Review URL: https://github.com/google/traceur-compiler/pull/1071

Closes #1071.
0.0.45
Move compile from src/node/api.js into src/Compiler

Fixes #1002
Improve temp variable handling for destructuring transformer

This fixes an issue where we added the temp variable outside the
function body when transforming destructuring for formal
parameters.

Fixes #1063
Refactor the compiler options.

Define default options in class constructors.
Export ToAmdCompiler and ToCommonJSCompiler with corresponding defaults.
Remove options unique to api (not on command line).
Add option moduleName (default true) to support commonjs w/o __moduleName.
Option moduleName takes string, empty string for no __moduleName, or '+' for
  resolve filename.

Review URL: https://github.com/google/traceur-compiler/pull/1079

Closes #1079.
Export default declarations should introduce a binding

`export default class C {}` should introduce a binding for C in
the current scope.

Fixes #1062
Remove invalid spread call optimization

Make sure that we always use the iterator for spread calls with only one
parameter.

Fixes #1049
Optimize how we validate cover grammar

When we convert a CoverFormals to a ParenExpression we only need
to check that there is no direct RestParam child.

For the CoverInitializedName we count the seen instances. Using
this we can determine if there have been any since an eralier
point in time and we can skip the expensive tree visitor.
Replace redundant low level calls with Compiler.compile().

Review URL: https://github.com/google/traceur-compiler/pull/1083

Closes #1083.
Revise Compiler API.

A step closer to a proposed API.

Remove unused Reporter params

Review URL: https://github.com/google/traceur-compiler/pull/1090

Closes #1090.