Replace g_breakpoints with a more robust breakpoint container.

[joekain]

Currently, the breakpoint module uses a fixed size array, g_breakpoints, to store breakpoints. This array and its usage have a number of limitations:

• Running out of space in the array is not handle gracefully
• Even when breakpoints are deleted the space is not reclaimed
• Enumeration of breakpoints is done manually by iterating over the array which leads to duplication
• Searches through the array are linear which could be made faster given a better structure

Acceptance Criteria:

• A new test exists that creates and destroys breakpoints over and over again such that at least 1000 breakpoints are created.
• The new test passes.
• All existing tests pass