Minor indentation fix

No changes were made to code. Just indentation fix.
Implemented 'rleindexlist' (.C and .R)

reimplementation of 'duplist'.
1) Now result vector is grown cleverly instead of over-allocating to length of input vector.
2) >= 2x speed-up on numeric type.
3) returns a list of length 2, first returns the index (unique positions) and second returns the corresponding lengths.
Updated NEWS and tests

Added tests for 'rleindexlist' and tested successfully.
Updated NEWS for 'radix order' and 'rleindexlist' under FR.
Various fixes - 'data.table' must be *significantly faster* on most operations.

>> removed fradix_order. added fastradixdouble and fastradixint. removed 'radixorder2' from 'setkey' and replaced it with 'iradixorder' and 'dradixorder' corresponding to int and double types.
>> modified 'fastorder' to use 'iradixorder' and 'dradixorder' instead of 'regularorder1' and 'ordernumtol'.
>> implemented 'rlixlist' (in C) and a R wrapper function with same name - faster version of 'duplist'. also incremental memory allocation. returns a list along with the length in addition to the indices now.
>> replaced 'duplist' (f__ and len__ calculations) in 'data.table.R' with 'rlixlist'. Also changed 'sort.list(.)' to 'dradixorder'.
>> modified previous tests by changing names wherever necessary, added new tests wherever appropriate and tested successfully.
>> NEWS (modified) and updated as well.
>> TO DO: replace 'duplist' and 'sort.list(...) in 'duplicated.data.table' and add tests.