#27 Add support for Epson L375 EcoTank

[Ivanilton Santos]

This patch adds the Epson L375 (EcoTank) to the ESC/P2 driver. The L375
shares the same print engine as the already-supported L310, so it reuses
model 129 with the existing cx3500 parameters. Only the printer entry is
added; no new model data is required.

Tested on CUPS: the PPD is generated as "Epson L375 - CUPS+Gutenprint
v5.3.5" and an A4 test page prints successfully.

Patch applies cleanly on top of gutenprint-5.3.5.

[Solomon Peachy]

Applied, thank you!