Tabs-to-spaces
Correct text of assertion-style error messages for undefined empty?, size, element methods.
Add support for printing general sequences to IO library.
Removed unused file that is implemented wrongly anyway.
Merge pull request #499 from BarAgent/hackathon

Minor fixes to collections support
[rt] Implement the leaf allocation functions.

This lets us implement more optimal forms of them.
[rt] Build runtime as -fPIC, since we link it dynamically.
[doc,hacker] Notes on debugging the compiler.
[doc,getting-started-cli] Explain stack traces.