Boost.Build Python port overall status

What works

• Interface between Python and Boost.Jam build engine is finished.
• Project loading and target declaration works
• Top-level code is ported, including getting build request, loading configuration files and projects and building/cleaning.
• A simple project with a 'make' rule loads and builds fine

Status of porting code modules

The below table documents the state of files in the 'build' directory. There, 'done' means the file is totally done, 'almost' means the file is essentially done, but maybe we tweaks are necessary as other files are ported and 'pending' is not yet there.

File	Lines	Status	Notes
targets.jam	1550	almost
feature.jam	1284	pending
virtual-target.jam	1231	almost	Need to fix dependency properties
generators.jam	1214	pending
project.jam	1018	almost
property.jam	694	pending
toolset.jam	510	pending
property-set.jam	464	almost
type.jam	370	pending
build-request.jam	301	pending
modifiers.jam	241	pending
scanner.jam	151	pending
alias.jam	75	done
version.jam	20	pending

Status of porting tools

We'll start by porting gcc, and proceed to other compilers only when all tests pass with gcc.

File	Lines	Status	Notes
python.jam	1167	pending
msvc.jam	1003	pending
builtin.jam	919	pending
gcc.jam	878	pending
common.jam	830	pending
qt4.jam	591	pending
testing.jam	518	pending
mpi.jam	501	pending
stage.jam	493	pending
doxygen.jam	459	pending
boostbook.jam	456	pending
quickbook.jam	314	pending
stlport.jam	296	pending
cw.jam	245	pending
gettext.jam	234	pending
qcc.jam	228	pending
borland.jam	224	pending
unix.jam	223	pending
qt3.jam	212	pending
hp_cxx.jam	168	pending
intel-win.jam	161	pending
rc.jam	155	pending
pathscale.jam	149	pending
mipspro.jam	145	pending
midl.jam	142	pending
pgi.jam	139	pending
symlink.jam	138	pending
sun.jam	137	pending
dmc.jam	134	pending
vacpp.jam	130	pending
whale.jam	116	pending
xsltproc.jam	112	pending
como-win.jam	112	pending
generate.jam	108	pending
acc.jam	107	pending
fop.jam	102	pending
intel-linux.jam	101	pending
como-linux.jam	101	pending
package.jam	98	pending
pch.jam	97	pending
darwin.jam	96	pending
cast.jam	89	pending
docutils.jam	81	pending
make.jam	73	pending
notfile.jam	71	pending
fortran.jam	55	pending
boostbook-config.jam	53	pending
quickbook-config.jam	44	pending
mc.jam	44	pending
ifort.jam	44	pending
xlf.jam	39	pending
gfortran.jam	39	pending
xsltproc-config.jam	37	pending
hpfortran.jam	35	pending
cw-config.jam	34	pending
lex.jam	33	pending
bison.jam	32	pending
intel.jam	30	pending
como.jam	30	pending
python-config.jam	27	pending
qt.jam	17	pending
msvc-config.jam	12	pending
doxygen-config.jam	11	pending

Post port: code cleanup

After all tests are passing with gcc, the following cleanups are desired:

• Convert all modules still using global variables to using 'context' object.
• Introduce Property class, and no longer store properties as specially formatted strings
• Introduce Feature class, and don't use icky dict.

Post port: design cleanup

• Use 'Metatarget' prefix for classes in the 'target' module
• Kill ProjectAttributes and keep all information about project inside ProjectTarget