Initial support for truecolor (xterm only)

Add e scr.truecolor variable
Add !! command to save history
Add ec: command to randomize palette
Minor rgb trash fix,
Initial import of the nodejs build system (far from complete)
Fix #133
r_bin: removed rva, offset and size from imports.

PLT-like lazy import wrappers are now part of symbols, where applicable.
The "imp." prefix is a temporary solution, it should be a flag.
r_bin: removed hint from RBinImport, as it's only used in PE and even there it's doubtfully relevant.
r_bin/ELF: don't ignore the r_addend field from Elf_Rela relocs.