⚡ Improve position UCI command parsing (I)

[eduherminio]

#405 until 032128b (1518)

Score of Lynx 1517 - parser vs Lynx 1502 - main: 5795 - 5833 - 4119  [0.499] 15747
...      Lynx 1517 - parser playing White: 3569 - 2209 - 2095  [0.586] 7873
...      Lynx 1517 - parser playing Black: 2226 - 3624 - 2024  [0.411] 7874
...      White vs Black: 7193 - 4435 - 4119  [0.588] 15747
Elo difference: -0.8 +/- 4.7, LOS: 36.2 %, DrawRatio: 26.2 %
SPRT: llr -2.95 (-100.2%), lbound -2.94, ubound 2.94 - H0 was accepted

Score of Lynx 1518 - parser vs Lynx 1502 - main: 5817 - 5851 - 4373  [0.499] 16041
...      Lynx 1518 - parser playing White: 3618 - 2239 - 2164  [0.586] 8021
...      Lynx 1518 - parser playing Black: 2199 - 3612 - 2209  [0.412] 8020
...      White vs Black: 7230 - 4438 - 4373  [0.587] 16041
Elo difference: -0.7 +/- 4.6, LOS: 37.6 %, DrawRatio: 27.3 %
SPRT: llr -2.96 (-100.4%), lbound -2.94, ubound 2.94 - H0 was accepted