Add JSON Helpers to TJsonObject for Delphi XE+

Addressing
https://github.com/fabriciocolombo/delphi-rest-client-api/issues/17
The property AsInt64 of TJsonNumber was included from Delphi XE2. Fixes #17 and closes #18
WinInet constants for Delphi XE compatability

The constants defined for Delphi < XE were introduced in XE2 so should
be defined for Delphi < XE2.
Revert "Add JSON Helpers to TJsonObject for Delphi XE+"

This reverts commit e9569c01fe35d034dae796a79b9bc3a230d403a1.
The property AsInt64 of TJsonNumber was included from Delphi XE2. Fixes #17 and closes #18
Remove backup *.~inc files from source directory

``DelphiRest.~inc`` doesn't need to be in the source. I've deleted it
and added a ``.gitignore`` entry to stop future ``.~inc`` files being
added.
Merge pull request #20 from thatalextaylor/master

Internet options for WinInet need to be defined for Delphi XE
Fixed list size bug. Added to/from datetime
Added missing bracket
Added OnError event with retry mode
Added HTTP PATCH method

http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods
Renamed retry methods
Better handle for empty responses
Made Super object default for XE and UP

Do we really need to have dbxjson as default?
I can't get it to parse even the simplest JSON.
Revert "Made Super object default for XE and UP"

This reverts commit fc4f082123dfcc62068807d0792c36bdce644a9c.
Fixed tests. Made ISO8601 optional.

The ISO 8601 format can be activated by defining it in the
DelphiRest.inc File.
Use: {$DEFINE ISO8601}

Atm. it is only supported for the superobject libary.
The superobject libary can be activated by removing:
{$IFDEF DELPHI_XE_UP}
  {$UNDEF USE_SUPER_OBJECT}
{$ENDIF}
from the DelphiRest.inc file.

dbxjson should support this too.
Fixed wrong ifdef
Merge pull request #24 from thomaserlang/master

More changes.
Add missing return values. Fix compiler directive in SuperObject. Fix packages for XE2.
Fix decoding of ISO 8601 Dates. to format the date in ISO 8601 standard the field must be annotated with attribute [JsonISO8601]