raw array indexing

Be able to turn off boo's array indexing normalization (that allows things like myarray[-1] like python), for speed purposes. See:
http://groups-beta.google.com/group/boolang/browse_frm/thread/f9673a6dfca8727b/1732e48b82f859a3?q=array#1732e48b82f859a3

This just adds simple macros. We can add a more general "options" macro or whatever later.

"""
normalarrayindexing is working
rawarrayindexing is working
time to set 10000 array items using rawarrayindexing
and then normalarrayindexing
"""

myarray = (1,2,3)

try:
normalarrayindexing:
myarray[-1] = 4
print "normalarrayindexing is working"
map(myarray,

)
except e:
print "error: you should not see me - normalarrayindexing is not working"

try:
rawarrayindexing:
myarray[-1] = 5
print "error: you should not see me - rawarrayindexing macro is not working"
except e as System.IndexOutOfRangeException:
print "rawarrayindexing is working"

//time how long it takes to set 10000 array items with rawarrayindexing on
a1 = array(int,10000)
a2 = array(int,10000)
start = date.Now

i = 0
while i < 10000:
j = 0
while j < 10000:
rawarrayindexing:
a1[i] = a2[j]
++j
++i

end = date.Now
print "T(raw) = " + (end-start)

start = date.Now

i = 0
while i < 10000:
j = 0
while j < 10000:
normalarrayindexing:
a1[i] = a2[j]
++j
++i

end = date.Now
print "T(normal) = " + (end-start)