Prettify compiler output for verbosity=1

Long lines displaying the invocation of the c compiler are replaced with short, readable lines.

**With this short example:**
```nimrod
import math

for i in 0..10:
    echo random(100)
```
**the previous default output that looked like this:**
```
$ nim c --hint[Path]:off --hint[Conf]:off random.nim
```
Hint: system [Processing]
Hint: random [Processing]
Hint: math [Processing]
Hint: times [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
lib/nimrod/pure/math.nim(199, 7) Hint: 'math.gettime(dummy: ptr cint): cint' is declared but not used [XDeclaredButNotUsed]
**gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/random.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/random.c 
gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/system.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/system.c 
gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/math.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/math.c 
gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/times.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/times.c 
gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/strutils.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/strutils.c 
gcc -c  -w  -I/usr/lib/nimrod -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/parseutils.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/parseutils.c 
gcc   -o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/random  /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/parseutils.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/strutils.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/times.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/math.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/system.o /home/wan/wherethefuckaremyfiles/NIMROD/small_tests_n_stuff/nimcache/random.o  -ldl -lm**
Hint: operation successful (11169 lines compiled; 1.105 sec total; 18.184MB) [SuccessX]

---
**is changed in the far prettier output:**
```
$ nim c --hint[Path]:off --hint[Conf]:off random.nim
```
Hint: system [Processing]
Hint: random [Processing]
Hint: math [Processing]
Hint: times [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
lib/pure/math.nim(200, 7) Hint: 'math.gettime(dummy: ptr cint): cint' is declared but not used [XDeclaredButNotUsed]
**CC: random
CC: stdlib_system
CC: stdlib_math
CC: stdlib_times
CC: stdlib_strutils
CC: stdlib_parseutils
[Linking]**
Hint: operation successful (11850 lines compiled; 1.133 sec total; 19.194MB) [SuccessX]

---
To see the horrible gcc lines, invoke with `--verbosity=2` or more.

Of course, I know about `--verbosity=0` if I don't want to see most compiler lines, but I prefer still having an output sometimes, particularily for long/semi-long compilation time (the nimrod compiler is a good example). Besides, I think we ought to have a better **default** output.

What do you think of it?