Reorg pyodide ns to separate emscripten details from public API

MAINT Refactor test web server to allow multiple instances and log capture

Guard against infinite recursion when converting self-referential data structures

MAINT: Use bitwise and rather than mod, for performance

Fix versioning for tags starting with a "v"

Add version information

Set ALLOW_MEMORY_GROWTH=1

MAINT: Remove filePackagePrefixURL: It is deprecated

Emscripten warns about this when -s ASSERTIONS=1

Vendor file_packager.py

MAINT: Update {chrome,firefox}_options to options

Update to Matplotlib 2.2.3

Update to pandas 0.23.4

Update to Numpy 1.15.1

Selenium is saying:

/home/circleci/repo/pyodide-env/lib/python3.7/site-packages/selenium/webdriver/chrome/webdriver.py:50: DeprecationWarning: use options instead of chrome_options
  warnings.warn('use options instead of chrome_options', DeprecationWarning)