Major source code optimization

In brief, what has been done:
  * all header files had [include guards](http://en.wikipedia.org/wiki/Include_guard) added
  * arginfo and class method tables were moved from headers to sources (exception: interfaces and bases classes have arginfo in the header — this allows to reuse it by the child classes and interface implementors)
  * source files do not `#include "phalcon.h"` anymore — they #include only the files they need
  * zend_class_entry definitions were moved from phalcon.c to respective source files — now if someone needs to add a new class, there are less places in the code to modify
  * gcc-compatible compilers are instructed to generate dependency files (*.d): this is what automake usually does but because PHP uses only autoconf, this had to be done manually (pros: if you change a file, all dependent files need to be rebuilt. Before this, if you touch a header file, `make` won't rebuild anything and you need to rebuild the entire project).

Why this is good:
  * the compiler has to process fewer files (when the source file #include'd phalcon.h, the compiler had to process all headers regardless whether the source file needed them)
  * include guards will allow to use static inline functions in the headers — this could be used to replace macros (functions are type safe, macros aren't)
  * less symbols are exposed, this reduces the size of the debug information and allows for extra optimizations.

Benchmarks:

**1.3.0 branch**
```
$ du -hs ext 
7,5M    ext

$ cd ext; time sh -c 'phpize --clean && phpize && ./configure CFLAGS="-O1 -g -Wall -Werror" && make -B -j75 install'

real    1m37.913s
user    3m17.824s
sys     0m46.596s

Max LA: 55.12

$ du -h modules/phalcon.so

193M    modules/phalcon.so

$ NO_INTERACTION=1 make test

=====================================================================
TEST RESULT SUMMARY
---------------------------------------------------------------------
Exts skipped    :    0
Exts tested     :   46
---------------------------------------------------------------------

Number of tests :   91                85
Tests skipped   :    6 (  6.6%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    0 (  0.0%) (  0.0%)
Expected fail   :    0 (  0.0%) (  0.0%)
Tests passed    :   85 ( 93.4%) (100.0%)
---------------------------------------------------------------------
Time taken      :   28 seconds
=====================================================================
```

**This branch:**
```
$ du -hs ext 
7,6M    ext

$ cd ext; time sh -c 'phpize --clean && phpize && ./configure CFLAGS="-O1 -g -Wall -Werror" && make -B -j75 install'

real    0m41.058s
user    1m13.126s
sys     0m37.876s

Max LA: 30.77

$ du -h modules/phalcon.so
9,6M    modules/phalcon.so

$ NO_INTERACTION=1 make test

=====================================================================
TEST RESULT SUMMARY
---------------------------------------------------------------------
Exts skipped    :    0
Exts tested     :   46
---------------------------------------------------------------------

Number of tests :   91                85
Tests skipped   :    6 (  6.6%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    0 (  0.0%) (  0.0%)
Expected fail   :    0 (  0.0%) (  0.0%)
Tests passed    :   85 ( 93.4%) (100.0%)
---------------------------------------------------------------------
Time taken      :   10 seconds
=====================================================================
```

Summary:
  * 1.3.0:
    * compilation time: 1m37.913s
    * max load average: 55.12
    * binary size: 193M
    * time taken for tests: 28 seconds
  * this branch:
    * compilation time: 41.058s (**58.07% faster**)
    * max load average: 30.77 (**44.18% less**)
    * binary size: 9.6M (**95.03% smaller**)
    * time taken for tests: 10 seconds (**64% faster**)