Fix #755
Formatting and rename makeNormalPath: to normalizePath:
Update API-CHANGES.txt
Tried to make consistent format in API-CHANGES.txt
Update API-CHANGES.txt
Uses `protocol` in CompiledMethod instead of `category` (mixed with protocol)
Uses protocol instead of category in method exports
Merge branch 'master' of github.com:amber-smalltalk/amber

Conflicts:
	API-CHANGES.txt
Update API-CHANGES.txt
amber.js tries to find itself also by id not just as last <script>

When loaded all scripts asynchronously, the
'last <script> tag' trick is unable to find the right one,
so amber.js does not see its path and possible data-libs.

In case of async loading, giving the <script> well-known id
'amber-path-mapper' allows it to find itself.
update CHANGELOG with async amber.js loading
Removed warnings for missing js/ and st/ directories
Commenting 'amber-path-mapper' id in "find myself" part
Readable error for library dependencies missing
chunk of error reported
Fixes issue #774
Merge pull request #771 from herby/alternate-find-amberjs-script

amber.js tries to find itself also by id not just as last <script>
Merge pull request #772 from herby/gh-770

Helps some parts of #770
Alert error message when class compilation fails in Environment
Warn the user when subclassing nil