New in 3.0.5: updated expressions

[Alan DeKok]

  The "expr" module has been updated in the v3.0.x branch, which will
become 3.0.5.

  The old version did not respect operator precedence.  It just
evaluated the string left to right.  This forced people to use (...) to
get the correct results.

  The new code implements precedence properly.  As a bonus, it now
supports bit shifts:

	1 << 3 == 8

  This is a minor feature which will make it easier to create simple
policies.

  Alan DeKok.