J-M-L:
NO you can' remove the *, it means it's a pointer... if you remove it then you've changed the behavior... you'll have bugs...for example this is how you declare individual strings in PROGMEM and then an array of those strings. Each entry in the array is a pointer.
#include <avr/pgmspace.h>
const char string_0[] PROGMEM = "String 0";
const char string_1[] PROGMEM = "String 1";
const char string_2[] PROGMEM = "String 2";
const char string_3[] PROGMEM = "String 3";
const char string_4[] PROGMEM = "String 4";
const char string_5[] PROGMEM = "String 5";
// Then set up a table to refer to your strings.
const char* const string_table[] PROGMEM = {string_0, string_1, string_2, string_3, string_4, string_5};
Oh. I knew that * means something.. but I tottaly forgot it means a pointer 
It's bad that I deleted the * then saved? But i put it back... Do i get bugs now too?
I put the * back and this is my error:
Arduino: 1.8.1 (Windows 7), Board: "Arduino/Genuino Uno"
In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:28:0,
from sketch\Chronos.ino.cpp:1:
Chronos:169: error: variable 'sentence_table' must be const in order to be put into read-only section by means of '__attribute__((progmem))'
const unsigned char *sentence_table[] PROGMEM = {
^
Chronos:188: error: variable 'bitmap_table' must be const in order to be put into read-only section by means of '__attribute__((progmem))'
const unsigned char *bitmap_table[] PROGMEM = {
^
exit status 1
variable 'sentence_table' must be const in order to be put into read-only section by means of '__attribute__((progmem))'
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
Can you still help me how to fix this? Please 
Should i change it to "const char* const XXX" like you linekd in the code?