Add additional flags for errors and warnings

- Improve Makefile
  - Support make <<object file>>
  - Remove .w.pdf: dependency
  - Add appropriate dependencies on each make target
  - Remove change file from dependency chain
- Add -Werror and -Wextra to gcc command line
- Remove @<Copyright...@> in tegen.w
- Add @<Copyright...@> to each module:
  - wp_tegen
  - wp_memory
  - wp_test
- Remove useless type qualifiers from:
  - wp_memory:wp_get_txn
  - wp_memory:wp_get_txn_head
- Change int to unsigned int on count to match type of wp_suites_count
  - Remove useless assert due to new type
- Change size_t r = 0; to ssize_t r = 0; to reflect proper return type
  of unistd.h:read.
In progress: Objectify wp_tegen module

wp_memory.w:
- Fix embarrassing test case fail in wp_memory in which WP_TEST_FAIL was
  not proceeded by WP_TEST_END. This breaks the tests
- Update test in wp_memory module to account for the delta between
  diagnostic totals before and after allocation
- Remove old wp_memory_print_stats() call in allocation tests; no longer
  required

wp_test.w:
- Add int * c parameter to wp_test_execute_tests to indicate whether or
  not tests are currently in progress
- IN PROGRESS: Update @<execute child process@> section to return rather
  than exit(ret). This changes the parent/child interaction, but it
  should be safe. Requires further testing

wp_tegen.w:
- IN PROGRESS: Flesh out module vs. object initialization, allocation,
  terminate and deallocation:
  - Modules: Initialize and Terminate
  - Objects: Allocate, Initialize and New; Delete, Terminate and
    Deallocate (New and Delete hurt, but I can't think of a better name
    right now. This API may change)
  - Remove public functions wp_tegen_initialize and wp_tegen_terminate
  - Add object wp_tegen with instance methods:
    - modules_initialize
    - modules_terminate
    - new
    - delete
    - free
  - Add module functions:
    - wp_tegen_init
    - wp_tegen_alloc
- Flesh out some functions for initialization, termination, new, delete,
  allocate and free. Will document these functions at a later time.

tegen.w:
- Move tty and i variables into inner block
- Remove wp_tegen_initialize and wp_tegen_terminate function calls
- Add new wp_tegen object
  - Initialize and new-up tegen instance
  - Call tegen instance modules_initialize
  - Fix error handling around atexit call
  - Check count return from wp_test_execute_tests and exit prematurely
    if the count > 0
  - Add error handler (out0) to delete the tegen instance and output an
    error message to stderr.