Don't pass linker flags during compilation

Linker flags are not needed when compiling source code (.cpp) to object files (.o).
Linker flags are needed only when linking all object files into executable
Add short makefile reference

Short reference/reminder of automatic variables used in recipes
Make 'makefile' more consistent in style

Spacing + use of automatic variables
Fix makefile - wx_fsqlf depends on basic_notepad
Fix `flex` command

Options have to be listed before the input file is provided
Add `DELETE` keyword form

Previously only `DELETE FROM` (i.e. 2 words) was recognized as a keyword.
It seems number of databases allow to use just `DELETE table <...>` (i.e. without `FROM`)
Recognize hexadecimal literals (mysql)

Example of hexadecimal literal in mysql: x'0f01ff'
Treat it as single token
(previously it was split into 2 tokens,
and spacing was inserted in the midle)

Solves: https://sourceforge.net/p/fsqlf/bugs/9/
Relevant mysql doc: http://dev.mysql.com/doc/refman/5.0/en/hexadecimal-literals.html
Fix build dependency: basic_notepad<-licence_text

Seem in progress of refactoring, license text was moved away from wx_fsqlf.cpp,
but makefile was not adjusted.
Shorten C++ building

1. Define generic rule for build c++ .o files using pattern
2. Separately describe dependencies
Fix formatting of scientific notation

Example of scientific number notation: 1e-10, 1e+10
Reported under: https://sourceforge.net/p/fsqlf/bugs/9/ (reused)
Move 'private' includes .hpp->.cpp

Licence text was in .hpp which it self was <include>'ed into other file,
this caused build error.