No longer include enum values that are NoCalls.

Some enum values in the WSDLs are marked as NoCalls. These don't need to be included in the SDK.
Don't generate php files for enums that contain no values.
Merge branch 'no-calls' into develop
Fix issues with fields that are xs:simpleType.

There were two issues.

1) PHP doc for enum properties was wrong.

  * @property DTS\eBaySDK\FindingAPI\Types\EnumStringType(string) $enumString

  This is now corrected.

  * @property DTS\eBaySDK\FindingAPI\Enums\EnumStringType(string) $enumString

2) Some eBay types are derived from xs:simpleType. XSLT was incorrectly
creating these as enums. These fields don't need to be a PHP class as
they can be represented with simple PHP types.
Merge branch 'simple-types' into develop