BaseTools: fix imports

1 - Some of these imports are cascaded from another file. Import them locally.
2 - Some of these imports are not used. Remove them.
3 - Some of these were missing the namespace used to import them.

These changes facilitate optimization of BaseTools:
https://bugzilla.tianocore.org/show_bug.cgi?id=42

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/Common/RangeExpression.py

@@ -19,6 +19,7 @@ from CommonDataClass.Exceptions import WrnExpression
 import uuid
 from Common.Expression import PcdPattern, BaseExpression
 from Common.DataType import *
+from re import compile
 
 ERR_STRING_EXPR = 'This operator cannot be used in string expression: [%s].'
 ERR_SNYTAX = 'Syntax error, the rest of expression cannot be evaluated: [%s].'
@@ -202,7 +203,7 @@ class RangeExpression(BaseExpression):
 
     NonLetterOpLst = ['+', '-', '&', '|', '^', '!', '=', '>', '<']
 
-    RangePattern = re.compile(r'[0-9]+ - [0-9]+')
+    RangePattern = compile(r'[0-9]+ - [0-9]+')
 
     def preProcessRangeExpr(self, expr):
         # convert hex to int