Update SpiderMonkey version

[janl]

Follow up for: #1334

Very WIP branch here: https://github.com/apache/couchdb/tree/sm52

The plan roughly is to bring our SM dependencies to a new release, which means rewriting a bunch of our C/C++ goop that binds SM to our CLI tool.

The newer version will not accept CouchDB-style function declaration as-is, but there are two options to deal with this:

1. the Chakra work included an auto-AST transform thinger to adjust things to we maintain backwards compatibility.
2. we bite the BC bullet, because the impact is mostly theoretical.

Benefits: faster js, modern JS language features, fewer packaging woes.

[denib]

@jiangphcn - do you have an update here? Tnx!

[jiangphcn]

thanks for checking @denib

I am working on this task using #2170.

Below is current status:

• codes of couch_js are updated to use SpiderMonkey 60
• couch_js can be compiled locally in mac environment
• the javascript for main.js is updated and is able to be compiled during runtime
• new couchjs can started by couchdb and communicated with couchdb to accept reset, addFun, mapDoc etc

There are some to-dos I am working on

• there is code tweak needed to complete the whole mrview action
• compile and test in linux and windows
• adding codes to workaround anonymous javascript function name
• test where multiple sandbox are working together.

Hope I can get more progress in coming weeks.