Log Message:
Update to 0.12.4

Upstream changes:
Changes in Rcpp version 0.12.4 (2016-03-22)

    Changes in Rcpp API:

        New accessors as() and clone() were added to the Nullable class (Dan in \ 
PR #423 closing #421)

        The Nullable<>::operator SEXP() and Nullable<>::get() now \ 
also work for const objects (Kirill Mueller in PR #417).

        A subsetting error was fixed (Qiang via #432 closing #431).

    Changes in Rcpp Sugar:

        Added new Sugar function median() (Nathan in PR #425 closing #424)

        Added new Sugar function cbind() (Nathan in PR #447 closing #407)

    Changes in Rcpp Attributes:

        A plugin for C++14 was added (Dan in PR #427)

    Changes in Rcpp Documentation:

        An entry was added to the Rcpp-FAQ vignette describing the required \ 
packages for vignette building (#422).

        Use on OS X was further detailed (James Balamuta in #433 with further \ 
review by Bob Rudis).

        An entry was added concerning the hard-code limit of arguments to some \ 
constructor and function (cf #435).

        The Rcpp-FAQ vignette now contains a table of content.

        Typos and indentation were corrected in the Rcpp Sugar vignette (#445 by \ 
Colin Gillespie).

Changes in Rcpp version 0.12.3 (2016-01-10)

    Changes in Rcpp API:

        Const iterators now CharacterVector now behave like regular iterators \ 
(PR #404 by Dan fixing #362).

        Math operators between matrix and scalars type have been added (PR #406 \ 
by Qiang fixing #365).

        A missing std::hash function interface for Rcpp::String has been addded \ 
(PR #408 by Qiang fixing #84).

    Changes in Rcpp Attributes:

        Avoid invalid function names when generating C++ interfaces (PR #403 by \ 
JJ fixing #402).

        Insert additional space around & in function interface (PR #400 by \ 
Kazuki Fukui fixing #278).

    Changes in Rcpp Modules:

        The copy constructor now initialized the base class (PR #411 by Joshua \ 
Pritikin fixing #410)

    Changes in Rcpp Repository:

        Added a file Contributing.md providing some points to potential \ 
contributors (PR #414 closing issue #413)

Changes in Rcpp version 0.12.2 (2015-11-14)

    Changes in Rcpp API:

        Correct return type in product of matrix dimensions (PR #374 by Florian)

        Before creating a single String object from a SEXP, ensure that it is \ 
from a vector of length one (PR #376 by Dirk, fixing #375).

        No longer use STRING_ELT as a left-hand side, thanks to a heads-up by \ 
Luke Tierney (PR #378 by Dirk, fixing #377).

        Rcpp Module objects are now checked more carefully (PR #381 by Tianqi, \ 
fixing #380)

        An overflow in Matrix column indexing was corrected (PR #390 by Qiang, \ 
fixing a bug reported by Allessandro on the list)

        Nullable types can now be assigned R_NilValue in function signatures. \ 
(PR #395 by Dan, fixing issue #394)

        operator<<() now always shows decimal points (PR #396 by Dan)

        Matrix classes now have a transpose() function (PR #397 by Dirk fixing #383)

        operator<<() for complex types was added (PRs #398 by Qiang and \ 
#399 by Dirk, fixing #187)

    Changes in Rcpp Attributes:

        Enable export of C++ interface for functions that return void.

    Changes in Rcpp Sugar:

        Added new Sugar function cummin(), cummax(), cumprod() (PR #389 by \ 
Nathan Russell fixing #388)

        Enabled sugar math operations for subsets; e.g. x[y] + x[z]. (PR #393 by \ 
Kevin and Qiang, implementing #392)

    Changes in Rcpp Documentation:

        The NEWS file now links to GitHub issue tickets and pull requests.

        The Rcpp.bib file with bibliographic references was updated.