OData - Improve handling of filter expressions

[GoogleCodeExporter]

The current handling of OData filter expression is very basic (<param> <op> 
<value>).
This must be improved to handle more cases:

- <value> <op> <param>
- OData functions
- more types (date, ...)

Ref:
VariantODataFilterQuery.java
http://www.odata.org/media/16352/[ms-odata].pdf

Original issue reported on code.google.com by patrick....@gmail.com on 27 Mar 2013 at 4:33

[GoogleCodeExporter]

Also support the option that an attribute may be used many times in the 
expression.
-> change the implementation by removing the Map in order to keep track of all 
instance of this attribute. 

Original comment by patrick....@gmail.com on 27 Mar 2013 at 5:13