[ex-15] Inflation calculation does not affect player starting money

[martin509]

Title. I noticed this on the most recent ex-15 beta build (commit 5c3d268 on ex-15-industry-growth-test).

Player starting money does not get inflation-adjusted currently, which means it only increases linearly by $1000 every year. This is obviously supoptimal because it makes starting a game in the modern era impossible due to lack of funds to purchase e.g. a starting bus depot, whereas starting in 1900 gives players ample capital to put down a few bus lines or a short passenger rail route. By 2000 this is at the point where a bus depot costs $1.6 million vs starting funds of $400,000, when inflation-adjusting the 1900 starting amount of $300,000 would be close to $1.6 billion in actual starting funds.

The fix should be simple, replacing the starting money calculation with an inflation adjustment of $300,000 from 1900. I would also suggest rounding to two significant digits just to simplify things.