Update github.com/floitsch/double-conversion to new location

Summary: Closes #212

Reviewed By: @JoelMarcey, @paulbiss

Differential Revision: D2144749

Pulled By: @sgolemon

README.md

@@ -84,7 +84,7 @@ of by the bootstrap script.)
 Other Linux distributions
 -------------------------
 
-- double-conversion (https://github.com/floitsch/double-conversion/)
+- double-conversion (https://github.com/google/double-conversion)
 
   Download and build double-conversion.
   You may need to tell configure where to find it.

folly/bootstrap-osx-homebrew.sh

@@ -19,7 +19,7 @@ brewget glog gflags boost libevent
 # NB their install target installs the libs but not the headers, hence the
 # CPPFLAGS
 test -d double-conversion ||
-    git clone https://github.com/floitsch/double-conversion.git
+    git clone https://github.com/google/double-conversion.git
 pushd double-conversion
 make
 # fool libtool into using static linkage

folly/configure.ac

@@ -78,7 +78,7 @@ AC_CHECK_HEADERS([fcntl.h features.h inttypes.h limits.h stdint.h stdlib.h strin
 
 AC_CHECK_HEADER(double-conversion/double-conversion.h, [], [AC_MSG_ERROR(
                 [Couldn't find double-conversion.h, please download from \
-                 https://github.com/floitsch/double-conversion/])], [])
+                 https://github.com/google/double-conversion/])], [])
 AC_CHECK_LIB([double-conversion],[ceil],[],[AC_MSG_ERROR(
              [Please install double-conversion library])])