feat(DEPENDENCIES): each file can specify its own dependencies

[pkozelka]

This introduces the DEPENDENCIES feature.
The goal is to resolve issue scijava#45

It allows to specify list of dependencies for every file, so that it is extracted into the same directory.
This allows complex sets libraries to be embedded properly and used from JNI, without affecting existing functionality.

Usage:

• let's say you have file libzoo.so which depends on libelephant.so and libtiger.so.1
• store libzoo.so as you do normally, for instance into linux_64 directory
• create file libzoo.so.DEPENDENCIES next to it, it's the dependency descriptor
• give it the following contents:

  libelephant.so
  libtiger.so.1
  

• add these two listed files next to the descriptor (= same path)

Then use as you normally do.

The descriptors are evaluated recursively, so every dependency can have its own dependency descriptor.