A cheap solution to the ASM issue

[nixietab]

As discussed in #45, picomc was loading both ASM 9.6 and 9.7.1 into the classpath. This commit adds a (cheap but effective) fix to prevent that.

The approach is:

• Tracks which artifact versions have already been loaded
• Prevents multiple versions of the same library from being added
• Handles ASM conflicts explicitly by allowing only one version (just to be safe)
• Uses simple version comparison to resolve other potential conflicts

I really hope it works