Turn modified fdlibm into Jerry's own libm

* Rename modified fdlibm to jerry-libm
  * Move third-party/fdlibm to jerry-libm
  * Rename original fdlibm.h to jerry-libm-internal.h
    * And remove it from the public headers.
  * Rename jerry-libm's public header to math.h
    * This also makes jerry-core sources include `<math.h>`. Therefore,
      should anyone want to use a different libm implementation with
      jerry, it becomes possible. (The same way as we provide a minimal
      libc with standard headers, but should it be insufficient or
      conflicting for someone, it can be replaced.)
  * Drop `s_` prefix from jerry-libm sources
    * The original fdlibm implementation had various prefixes (e.g., `k_`
      for sources of kernel routines, and `w_` for wrapper routines), but
      after the specialization of fdlibm to jerry, only `s_` remained.
      Since it does not encode anything anymore, it can be dropped.
  * Stylistic edits to jerry-libm's CMakeLists
    * Align project name with other CMakeLists in the code base
  * Move Jerry-LibM under Apache License
    * Using the same approach as was used by linux-wireless when ath5k
      driver license needed clarification. Solution was proposed by SFLC.
      External mail for future reference: http://lwn.net/Articles/247806/

* Tests & checks
  * Remove FD from the name of libm unit test-related files
  * Make vera++ and cppcheck check jerry-libm

* Targets
  * Speculative update of targets to use jerry-libm

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

targets/esp8266/Makefile

@@ -1,4 +1,4 @@
-# Copyright 2015 Samsung Electronics Co., Ltd.
+# Copyright 2015-2016 Samsung Electronics Co., Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -86,7 +86,7 @@ LINKFLAGS_eagle.app.v6 =				\
 	-L./libs					\
 	-ljerrycore					\
 	-ljerryentry					\
-	-lfdlibm					\
+	-ljerrylibm					\
 	$(DEP_LIBS_eagle.app.v6)			\
 	./libs/lib_a-setjmp.o				\
 	-Wl,--end-group
@@ -96,7 +96,7 @@ DEPENDS_eagle.app.v6 =					\
 	$(LD_FILE)					\
 	$(LDDIR)/eagle.rom.addr.v6.ld			\
 	./source/jerry_targetjs.h			\
-	./libs/libfdlibm.a				\
+	./libs/libjerrylibm.a				\
 	./libs/libjerrycore.a				\
 	./libs/libjerryentry.a