SEATTLE — The Astros spent spring training insisting they were going to exceed the baseball world’s low expectations for a $20 million team that’s rebuilding on multiple levels. The club can still do that: 155 games and more than five months of baseball remain. But seven games into the 2013 regular season, the Astros are showing signs of feeling the pressure of a six-game losing streak that’s seen the team set several MLB offensive strikeout records. And two key veterans said Monday after a 3-0 loss to the Mariners — the Astros’ third shutout in seven games — the club must stick together through an initial wave of adversity. The [...]