Remove <cxxflags> and other cruft from Jamfile (#557)

The warnings, debug-symbols and other build properties
can (and should) be controlled via b2 command line options.

By the way, most of <cxxflags> uses in Jamfile-s are usually incorrect.
Instead, better option is to:
  use warnings=pedantic to control the warnings instead of cxxflags options directly
  either in requirements or in default-build,
  depending on whether you want to override it from the command line or not

test/Jamfile

@@ -22,18 +22,6 @@ project
     <include>.
     # TODO: Enable concepts check for all, not just test/core
     #<define>BOOST_GIL_USE_CONCEPT_CHECK=1
-    <toolset>msvc:<define>_SCL_SECURE_NO_DEPRECATE
-    <toolset>msvc:<define>_CRT_SECURE_NO_WARNINGS
-    <toolset>msvc:<define>_CRT_NONSTDC_NO_DEPRECATE
-    <toolset>msvc:<define>NOMINMAX
-    <toolset>intel:<debug-symbols>off
-    <toolset>gcc:<cxxflags>"-fstrict-aliasing"
-    <toolset>darwin:<cxxflags>"-fstrict-aliasing"
-    # variant filter for clang is necessary to allow ubsan_*
-    # custom variants declare distinct set of <cxxflags>
-    <toolset>clang,<variant>debug:<cxxflags>"-fstrict-aliasing"
-    <toolset>clang,<variant>release:<cxxflags>"-fstrict-aliasing"
-    $(DEVELOPMENT_EXTRA_WARNINGS)
     [ requires
         cxx11_constexpr
         cxx11_defaulted_functions