Remove the lock for IsConnectionAlive get method

[limaolm]

Hi Woong,

Thanks for create and open source EpServerEngine.cs. It's a great project. However, I found the performance can be greatly improved in some case by a minor change. The get method of IsConnectionAlive property does not need to be guarded by m_generalLock lock. It's bool type. If a caller client need to query IsConnectionAlive in a loop, the unnecessary lock might introduce race condition/wait with other operations.

public bool IsConnectionAlive
{
get
{
lock (m_generalLock)
{
return m_isConnected;
}
}
private set
{
lock (m_generalLock)
{
m_isConnected = value;
}
}