Improvements from Undergraduate Thesis Work

[yungcomputerchair]

Sorry it took so long for me to put this together, but this PR should bring in the core improvements discussed in my paper. This includes:

• Stack memory simulation
• memset call detection & simulation
• Duplicate execution path culling and path quantity limit
• Pre-indexed ("write-back") addressing mode
  • note that the paper also discusses post-indexed addressing mode, but I did not get around to implementing it
• Support for negative offsets in offset addressing mode
• Small fix for multi-byte memory reads