big memory leak

A COODBMS deleteBranch opens up a huge hole--we've got a grade A #1 memory leak here.

Here's some sample output from the validate utility after running createBranch/deleteBranch a few times. The format is simple, block location + length = starting address of unaccounted memory. Basically I just built a table of all available, freed and in use memory and combined adjacent blocks. When things are working, there should only be one big block with a starting location of 512.

512 + 320 = 832
85312 + 64 = 85376
89920 + 192 = 90112
127744 + 64 = 127808
169792 + 64 = 169856
211776 + 4480 = 216256
216448 + 128 = 216576