Simplemonitor

* REQUIRE PYTHON >= 3.5
* Switch to distribution as a pip package! You can now "pip install simplemonitor"
* Add memory monitor
* Add Ring doorbell monitor (checks battery level)
* Add support for checking file is not too large
* Add support for running a command when a monitor recovers
* Add support for reloading config on the fly
* Fixes to compound monitor logic
* HTTP monitor can check both return code and regexp now
* Update pkgaudit monitor to chase new output format
* DNS monitor can check response is NXDOMAIN
* Many code quality improvements (I hope)

* REMOVED SUPPORT FOR Python 2.6

+ Add Slack alerter
+ Add Command monitor
+ Add pkg audit monitor
+ Add SSL client auth
+ Add Amazon SES alerter
+ Add a sample upstart script
+ Add support for Pushover
+ Add support for alerters to repeat
+ Support username/password and SSL support for SMTP
* Use subprocess everywhere
* Honour SMTP port in configuration
* Honour gap configuration option
* Use HTTPS for BulkSMS API
* Date format for logfile is configurable
* Use UTC everywhere for times; should fix monitors which have been down -1 hours
* Teach the host (ping) monitor to use command line options better on
different operating systems
* Verify dependencies exist
* Stop alerters from firing success notifications out-of-hours

* Added DNS monitor
* Added Execute logger

* Fixed a problem where success alerts were always sent
* Many other small fixes

+ Added remote monitor/central reporting support
+ Added support for monitor defaults
+ Added HTML logger type to generate a status webpage
+ Added syslog alerter

+ Added -p option to write a pidfile
+ Added support for a HUP signal to close/reopen logfiles