Revert "Remove redundant utcnow function"

This reverts commit d37dc92d8e9ddfb251a3a2ca573733a3ec92db68.
Revert "Use arrow for datetime handling"

This reverts commit 1fdceb423074e5ce36777400cd2c7bbbb2c795ca.

Conflicts:
	extra/requirements-base.txt
	rdial/cmdline.py
	rdial/utils.py
Attempt to parse --time using system's date command

Systems using GNU's date command suddenly have a huge number of input formats
available.  Unlike the common Python modules for date parsing this method won't
produce invalid results by assuming mid-endian either.
Cache read CSV files

Refs #17.
Handle broken cache files

This is partly to support people who've upgraded/downgraded their Python
interpreter to one which doesn't support the currently used pickle format.  It
makes more sense than forcing a lower quality common version.
Add interactive message support

This is disabled by default, frankly because I don't like it.  Nudge me if you
think it should be enabled by default.
Switch to tabulate for report formatting

tabulate supports a variety of interesting output formats, and this makes it
easy to embed reports in to other documents.  EoM timesheet, I'm looking at you!
[Tr] Remove leftover arrow references
Make data caching optional
Merge branch 'f/datetime_handling'

Closes #18.

* f/datetime_handling:
  [Tr] Remove leftover arrow references
  Attempt to parse --time using system's date command
  Revert "Use arrow for datetime handling"
  Revert "Remove redundant utcnow function"

Conflicts:
	rdial/cmdline.py
	rdial/utils.py
Merge branch 'f/tabulate'

Closes #21.

* f/tabulate:
  Switch to tabulate for report formatting

Conflicts:
	rdial/cmdline.py
Use ciso8601 for speedy datetime parsing
Merge branch 'f/ciso8601'

Closes #22.

* f/ciso8601:
  Use ciso8601 for speedy datetime parsing
Merge branch 'f/cache_csv'

Closes #19.

* f/cache_csv:
  Make data caching optional
  Handle broken cache files
  Cache read CSV files

Conflicts:
	rdial/cmdline.py
	rdial/events.py
Merge branch 'f/interactive_messages'

Closes #20.

* f/interactive_messages:
  Add interactive message support

Conflicts:
	doc/api/utils.rst
	rdial/cmdline.py
[Tr] Remove redundant whitespace in doap file
[QA] Remove blessings references
Release 0.14.0