Support abbreviated numbers as command line input

[rvesse]

Currently options and arguments which have integer numeric types rely on those types parsing methods which require numeric values to be stated in full. When a command expects to receive large numerical values this can be very error prone for end users. Therefore it would be nice if it was possible to configure Airline such that abbreviated forms would be accepted e.g. 25M would translate to 25000000

This can be done by extending the existing type converter and overriding the portion that deals with converting simple types. As with most things we probably want to make this configurable both in terms of what suffixes are acceptable and how they are interpreted. Therefore the following implementation is suggested:

• New NumericTypeConverter Interface that deals with common numeric types
• existing default type converter takes an instance of this
• new default implementation of the new interface that extracts out the current default logic
• new abstract implementation of the new interface that permits abbreviated numerics. This implementation should have extensible methods that cover interpreting and expanding the suffixes
• two variants derived from this abstract implementation which cover the common set of suffixes interpreting them according to the notion of 1000 and 1024 being the base multiplier

[rvesse]

A nice to have but more complex extension would be to allow specific options to have specific converters that allow you to mix different abbreviation formats in a single command

Another extension would be to support stating numeric values in other common formats such as octal and hexadecimal

[rvesse]

This is now mostly implemented, mainly needs more test cases to check the overriding works as Designed