Removing question marks from new titles

ch01.asciidoc

@@ -17,7 +17,7 @@ Behind the scenes, bitcoin is also the name of the protocol, a network and a dis
 
 In this chapter we'll get started by explaining some of the main concepts and terms, getting the necessary software and using bitcoin for simple transactions. In following chapters we'll start unwrapping the layers of technology that make bitcoin possible and examine the inner workings of the bitcoin network and protocol. 
 
-=== Before Bitcoin?
+=== Before Bitcoin
 
 The emergence of viable digital money is closely linked to developments in cryptography. This is not surprising when one considers the fundamental challenges involved with using bits to represent value that can be exchanged for goods and services. Two fundamental questions for anyone accepting digital money are:
 
@@ -37,7 +37,7 @@ Bitcoin represents the culmination of decades of research in cryptography and di
 * A de-centralized mathematical and deterministic currency issuance (distributed mining), and;
 * A de-centralized transaction verification system (transaction script).
 
-=== History of Bitcoin?
+=== History of Bitcoin
 
 Bitcoin was invented in 2008 by Satoshi Nakamoto with the publication of a paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System". Satoshi Nakamoto combined several prior inventions such as b-money and HashCash to create a completely de-centralized electronic cash system that does not rely on a central authority for currency issuance or settlement and validation of transactions. The key innovation was to use a Proof-Of-Work algorithm to conduct a global "election" every 10 minutes, allowing the de-centralized network to arrive at _consensus_ about the state of transactions. This elegantly solves the issue of double-spend where a single currency unit can be spent twice. Previously, the double-spend problem was a weakness of digital currency and was addressed by clearing all transactions through a central clearinghouse.