Initial commit
Added OF-Config 1.1 XSD schema
Schema source:
https://www.opennetworking.org/images/stories/downloads/of-config/of-config-1.1.pdf

Schema is a well-fomed XML but doesn't validate with Apaches Xerces.
Fixed wrong type reference in OF-Config 1.1 XSD schema
Fixed OF-Config 1.1 XSD schema by adding missing 'ds' namespace import.
Changed wrong reference to 'ds:KeyValueType'.
Fixed OF-Config 1.1 XSD schema. Added 'xs' namespace to 'base64Binary'
Added XSD schema for XML crypto signatures.
It provides namespace 'ds' required by OF-Config 1.1 XSD schema.
Schema source:
http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd
Added XSD schema for Internet addresses and related things.
It provides namespace 'inet' required by OF-Config 1.1 XSD schema.
Added OF-Config 1.0 XSD schema.
Schema is well-formed and valid according to Apache Xerces.
Schema source:
https://www.opennetworking.org/images/stories/downloads/of-config/of-config1dot0-final.pdf
Commented out part of the ietf XSD schema.

Union types were causing Xmerl crash during schema parsing:

{error,[{[],xmerl_xsd,
    {type_not_uniquely_defined_in_schema,{'_xmerl_no_name_',['_xmerl_no_name_',
                                             'ip-address'],
                                             'urn:ietf:params:xml:ns:yang:ietf-inet-types'}}},
    {[],xmerl_xsd,
        {type_not_uniquely_defined_in_schema,{'_xmerl_no_name_',['_xmerl_no_name_',
                                                 'ip-prefix'],
                                                 'urn:ietf:params:xml:ns:yang:ietf-inet-types'}}},
    {[],xmerl_xsd,
        {type_not_uniquely_defined_in_schema,{'_xmerl_no_name_',['_xmerl_no_name_',
                                                 host],
                                                 'urn:ietf:params:xml:ns:yang:ietf-inet-types'}}}]}
Changed 'private-key' element type to 'xs:string' from 'ds:KeyValueType'.

Done in order to avoid Xmerl bug when validating XML agains schema:

{error,[{"capable-switch[1]/resources[6]/owned-certificate[6]",
    xmerl_xsd,
    {unexpected_rest,[{xmlElement,'RSAKeyValue','RSAKeyValue',
                          [],
                          {xmlNamespace,'urn:onf:params:xml:ns:onf:of12:config',
                              [{"xsi",'http://www.w3.org/2001/XMLSchema-instance'},
                              {"ds",'http://www.w3.org/2000/09/xmldsig#'}]},
                              [{'private-key',6},
                              {'owned-certificate',6},
                              {resources,6},
                              {'capable-switch',1}],
                              2,[],
    ...
Changed 'xs:union' elements to contain memberType attributes.

Original ietf XSD had no memberType attributes set for any of xs:union
elements. Instead 'xs:union' contained set of 'xs:simpleType' elements
with restriction to be based on certain type - the desired member type
of the union.

While this construction was parsable by Apache Xerces, Xmerl had
problems with it. Changing it to more canonical form, by utilizing
memberType attribute of the 'xs:union' element solved the issue.
Restored 'private-key' element type to 'ds:KeyValueType' from 'xs:string'.

Problem fixed by commit 37aad65420cf was caused by the usage of
'mixed=true' argument in the definition of complexType 'ds:KeyValueType'
in xmldsig-core-schema.xsd. Changing 'mixed' to false satisfies Xmerl
XSD parser. This change shouldn't affect the schema itself, because
we don't expect to see any mixed content inside 'ds:KeyValueType'
type anyhow. Actually XML with mixed content should be treated as
malformed.
Added preliminary parsing of OF-Config XML documents provided as Xmerl records.
Parsing of the OF-Config 1.1 Xmerl record structure to the internal record representation
Fixed eunit tests to work with jenkins
Replaced local include_lib with include
Full encoding/decoding of OF-Config 1.1 XML
Added OF-Config 1.1.1 XSD schema
Changed type of flow-table element from integer to string
of_config:encode/1 now return Xmerl simple format tuple instead of XML string