Optimize java classes for library use

[Tiihott]

Description
Optimize the the java classes for using rsm_01 as a library for record schema mapping, the usage of the library shouldn't require any additional dependencies and it should be easy to use.

Exception handling must also be implemented in java classes according to the liblognorm API documentations specified method return values. Errors are expressed with null, -1 and other return values in the API.
A thing to keep an eye on in the exception handling is the logic how liblognorm logs errors, for example loading a rulebase may trigger an error log message even though the method in question returns a 0 stating that the loading of the rulebase was a success.

[Tiihott]

Created separate issue for implementing exception handling.

[Tiihott]

Almost all Liblognorm library methods require the ln_ctx object, which is the the library context descriptor, as input argument.
By encapsulating the ln_ctx pointer inside the java object that interacts with the liblognorm library, it would give the java object its identity and remove the requirement of jna.Pointer usage outside the rsm_01 library.

Methods that do not require the ln_ctx pointer as an input argument can in turn be made into "smarts".