Introduce dxpy.cli.INTERACTIVE_CLI

This should be used when determining whether to use interactive prompts, instead of sys.stdin.isatty() or sys.stdout.isatty().
[PTFM-11713] Expand tests for dx-app-wizard
Revert part of c6d5755, will fix in a branch later
Truncated requests may only be retried if route is idempotent.

* Update retry logic documentation to reflect this.

* Previously, truncated requests would always be retried. This could
  have caused the requested action to be repeated twice. However,
  perhaps this change is somewhat academic since I don't know if short
  responses can or are likely to get truncated in arbitrary places, and
  most or all requests with long responses are idempotent anyway.
Javadoc fix: arguments of nested class types must be qualified
Use unicode for test app directory names
Bump nose from v1.3.1 to v1.3.3
Decode subprocess stderr as well as stdout
Fix unicode handling issues in environment variable I/O on Python 2
Merge pull request #68 from dnanexus/unicode-fixes

Unicode fixes
Update Travis config
Fix refactoring error and eliminate code block that was silently broken
Don't hardcode python 2.7 in Makefile
Always line buffer sys.stderr wrapper
Revert "Don't hardcode python 2.7 in Makefile"

This reverts commit 983658c8113300a5bf8385abdc725d99d8422309.
Changelog and version updates for v0.100.0
Include new requirements spec files
Generalize requirements file include
Eliminate use of nosetests, which has i18n bugs
Use encoding from locale (it seems to be absent as a stream attribute sometimes)