Remove cppcheck and vera++ from prerequisites

Rely on platform-provided versions. Thus, no need to download and
build them, neither to wrap them with shell scripts. CMake and
precommit updated to call the new tools. Development documentation
also updated/simplified.

PS: On my Ubuntu 14.04.3, cppcheck has version 1.61, while prereq
version was 1.69. The older version reports and fails on a strange
style issue in ecma/builtin-objects/ecma-builtin-helpers.cpp, for
which the only solution found was to suppress the cppcheck errors
with `variableScope` id for that file.

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

tools/precommit.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-# 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.
@@ -40,7 +40,7 @@ VERA_DIRECTORIES_EXCLUDE_LIST="-path ./third-party -o -path tests -o -path ./tar
 VERA_CONFIGURATION_PATH="./tools/vera++"
 
 SOURCES_AND_HEADERS_LIST=`find . -type d \( $VERA_DIRECTORIES_EXCLUDE_LIST \) -prune -or -name "*.c" -or -name "*.cpp" -or -name "*.h"`
-./tools/vera++/vera.sh -r $VERA_CONFIGURATION_PATH -p jerry $SOURCES_AND_HEADERS_LIST -e --no-duplicate
+vera++ -r $VERA_CONFIGURATION_PATH -p jerry $SOURCES_AND_HEADERS_LIST -e --no-duplicate
 STATUS_CODE=$?
 
 if [ $STATUS_CODE -ne 0 ]