Merge pull request #346 from lowjoel/unify-edit-add-syntax

Unify edit add syntax
Update boost and install the date time package
Merge pull request #348 from evansb/update-boost

Update boost and install the date time package
Refactor these copy-paste tests.
Test for the removal of subtasks and dependencies.
Implement tests for attachments.
Add test case for adding task with dependencies.
Define a fatal() macro that will assert and break the program unless it is in code coverage mode.
Move the anonymous namespace to the named namespace so we can exclude it from code coverage analysis.
Remove dead code.
Use bind to reduce code coverage false negative.
Implement "this Xday". Fixes #329.
Implement ignoring trailing whitespace when using the parse helper. Fixes #342.
Implement "this Month"
When specifying relative months, use the first day of the month.
Handle trailing characters not being consumed by rules. It is incomplete, so a parse failure.
Add long forms of the months and day of week. Fixes #343.
Support 'today'
Completed as an alias for complete.
Lint fixes.