Added SubtractPipe and AddPipe

[ghost]

I added the functions for SubtractPipe and AddPipe. These are used as:
{{ mydate | amAdd : '2' : 'hours' }}
{{ mydate | amSubtract : '2' : 'hours' }}

[pisix]

@urish please can you merge this PR ?

[urish]

Eventually yes, but first of all I want to make sure that the existing project works with all setups (Ionic, rollup, protractor, AMD) and release 1.0.0. You can see #90, #91, #89 , #87, #85 , #82, #80 as examples for such issues

[urish]

@dustin486 Hi, can you please update the PR to align the file names with angular2 style guide convention?

i.e. use add.pipe.ts instead of AddPipe.ts, etc.

I would love to see this feature as part of the upcoming 1.1.0 release :)

Thanks!

[ghost]

@urish Sure. I am at work until later tonight, but will do this tomorrow.

[urish]

Much appreciated!

[urish]

Ping

[ghost]

@urish Sorry, I've been sick for a few days, still am. I don't know what happened to this one, but I messed it up merging my local copy with your version. I just created another fork, updated mine, and opened a new PR: #113

This one can be closed. Sorry about the confusion.

[urish]

I hope that you feel better now :-)

I will take a look at #113 soon!