High performance nolock functions for SASIndex_t

        * /src/sasindex.cpp (SASIndexPercentFree): Replace divide by
        power of 2 with __builtin_ctzl and shift right.
        (SASIndexPercentUsed): Like wise.
        (SASIndexGetRootNode_nolock): New function.
        (SASIndexGetModCount_nolock): Like wise.
        (SASIndexGetMaxKey_nolock): Like wise.
        (SASIndexGetMinKey_nolock): Like wise.
        (SASIndexContainsKey_nolock): Like wise.
        (SASIndexGet_nolock): Like wise.
        (SASIndexIsEmpty_nolock): Like wise.
        (SASIndexPut_nolock): Like wise.
        (SASIndexReplace_nolock): Like wise.
        (SASIndexRemove_nolock): Like wise.
        (SASIndexPut): Update calls to SASIndexNodeInsert() and
        SASIndexNodeInitialize().
        (SASIndexRemove): Update call to SASIndexNodeDelete().
        * /src/sasindex.h: Add comment.
        (SASIndexGetModCount_nolock): Declare with comment.
        (SASIndexGetMaxKey_nolock): Declare with comment.
        (SASIndexGetMinKey_nolock): Declare with comment.
        (SASIndexContainsKey_nolock): Declare with comment.
        (SASIndexGet_nolock): Declare with comment.
        (SASIndexIsEmpty_nolock): Declare with comment.
        (SASIndexPut_nolock): Declare with comment.
        (SASIndexReplace_nolock): Declare with comment.
        (SASIndexRemove_nolock): Declare with comment.
        * src/sasindexenum.cpp (SASIndexEnumNext_nolock): New function.
        * src/sasindexenum.h (SASIndexEnumNext_nolock):
        Declare with comment.
        * /src/sasindexpriv.h (SASIndexGetRootNode_nolock):
        Declare with comment.

        * /src/tests/sasindex_tt.c (sassim_index_random_nolock):
        New Function.
        (sassim_index_sequential_nolock): Like wise.
        (main): Call sassim_index_random_nolock and
        sassim_index_sequential_nolock.