relax SVN archive

The package initialisation file '__init__.py' has been added to the 'scons' directory.

The 'sconstruct' script has been split in half. The script was copied to 'scons/manuals.py' and
only the manual compilation functions remain in this file. The class structure has been eliminated
from 'scons/manuals.py' so 'sconstruct' now imports each function from this module. This means that
4 spaces have been removed from the indentation. All the manual compilation Environment setups,
custom BUILDERS actions, and Depends statements have been shifted to the 'self.__init__()' function
of the 'sconstruct' script.

The default values of None for the target functions have been removed as they are always passed to
the functions. For example
def dummy(self, target=None, source=None, env=None):
has been changed to
def dummy(self, target, source, env):

Environmental variables such as LATEX_DIR, SYSTEM, BIN_PATH, etc. (all the variables created in
'self.paths()') are now placed in the Scons Build Environments. The Environment is passed into each
function as 'env' so the variables are accessed by typing, for example, env['LATEX_DIR']. The
variable 'self.system' has been renamed to 'self.SYSTEM'.

The 'self.gpg_bin_sign()' and 'self.gpg_src_sign()' target functions have been merged into the
single function 'self.gpg_sign()'.